In keeping with our current findings and previous studies that serum CN-1 correlates with renal tubular kidney injury molecule (KIM-1) staining of biopsies from patients with DKD, serum and urinary CN-1 might be a surrogate marker for both glomerular and tubular injury that to some extent may predict the course of DKD. The gene discussed is CNDP1; the disease is diabetic kidney disease.